In electronic equipments such as liquid crystal displays, mobile information devices such as mobile phones and tablets, digital cameras, organic EL displays, organic EL lightings, and sensors, in addition to miniaturization and thinning, higher performance has been required. As a method for manufacturing these electronic equipments at lower costs, a printed electronics in which wiring is directly printed has attracted attention. Manufacture of electronic components by a printing method can typically skip a multistage process including exposure and development and a vacuum process such as a vapor deposition method and thus substantial simplification of processes is expected.
Since a printing method such as inkjet or screen printing, gravure printing, or gravure offset printing can form a wiring with a desired pattern directly on a substrate, the method is used as a convenient and low-cost process. However, upon formation of a wiring with a desired pattern, as a result of flowing of a film-forming material used, wet-spreading and bleeding thereof occurs and thus there is a limitation on the formation of a fine pattern excellent in linearity.
Also, a technique of patterning a film-forming material by printing and forming a metal wiring by heat-burning or light-burning has been actively studied (for example, see Patent Document 1). However, in addition to the problem of spreading and bleeding of the material upon printing, there has been a problem in the adhesion of the resulting wiring to the substrate.
Therefore, for solving the aforementioned problems to enable high-definition printing and for forming a high-definition film, a technique of providing a wiring base-serving layer (underlying layer) has been studied. A base treatment for providing the underlying layer is often performed for the purpose of suppressing wet-spreading and bleeding of the film-forming material applied on the substrate to improve printability.
For example, a technique of grafting an epoxy group to a substrate is known (for example, see Patent Documents 2 and 3). Also, a technique of applying a photocatalyst onto a substrate is known (for example, see Patent Documents 4 and 5). Furthermore, a technique of applying an acrylic copolymer onto a substrate is known (for example, see Patent Documents 6 and 7).